The comma butterfly has taken advantage of warmer temperatures(Image: Robert Thompson/Butterfly Conservation)

By BBC News Online's Helen Briggs

Loss of habitat and climate change are having a devastating effect on British butterflies, say conservationists.

Unless we do something about the destruction of wildlife habitats in Britain, we will have failed to preserve our native wildlife heritage for future generations of people to enjoy

Richard Fox, Butterfly Conservation

According to a nationwide study, three-quarters of species have declined over the past 30 years.

The main factor is the destruction of habitat, say experts from wildlife charity Butterfly Conservation and three UK universities.

Wild meadows, ancient woodland, and moors where butterflies breed have been lost to farming, they say.

Limited range

With the recent rise in temperatures across the UK, one would think the prospects for heat-seeking butterflies were good, but three-quarters of the 46 butterfly species studied have been found to be in decline.

"Britain is right on the edge of the range of a lot of butterflies which are more at home in warmer parts of Europe," Richard Fox of Butterfly Conservation, in East Lulworth, Dorset, told BBC News Online.

"We would expect most species of butterfly in Britain to have done well in the global warming that we have seen over the last few decades.

"The negative effect is due to the loss of habitats - such as flower-rich grasslands, ancient woodlands and heaths - which has greatly outweighed the positive effects that we expected from the warming climate."

Warmer Britain

Records show that spring and summer in Britain has warmed by 1-1.5 C, in the past 25 years. Meanwhile, intensive agriculture has eroded 70% of semi-natural habitats since 1940.

Both factors have had an impact on butterflies, say scientists. While some species, such as the comma butterfly, have been able to spread further north to take advantage of warmer temperatures others have been unable to adapt.

Areas where butterflies breed have been lost to farming

Experts are warning that the countryside will look very different to future generations.

"Unless we actually do something about the destruction of wildlife habitats in Britain, many species, including some butterflies, will become rarer or extinct and we will have failed to preserve our native wildlife heritage for future generations of people to enjoy," Mr Fox told BBC News Online.

"Changing habitat and global warming will lead to fewer species," he added. "Many of the special, rare ones will go."

The research was carried out in collaboration with the universities of Leeds, York, and Durham.

The analysis, published in the journal Nature, is based on a huge survey involving 10,000 volunteers in the UK between 1995 and 1999.